The conversion of 3,4-cis- to 3,4-trans-cannabinoids

Δ9-cis-Tetrahydrocannabinol: Natural Occurrence, Chirality, and Pharmacology

“…In isomerization experiments with Lewis acids, scalemic (+)-Δ 9 - cis -THC [(+)- 3 ] was converted into (+)-Δ 8 - trans -THC [(+)- 4 ] of similar enantiopurity (Scheme ). , To account for epimerization at C-6a, the authors proposed a reversible isomerization pathway that involved both the cannabidiol olefin isomer 5 and cannabidiol 2 as intermediates (Scheme ). , This result suggested that Δ 9 - cis -THC could originate from CBD or at least that it could be biogenetically related to this compound.…”

“… , To account for epimerization at C-6a, the authors proposed a reversible isomerization pathway that involved both the cannabidiol olefin isomer 5 and cannabidiol 2 as intermediates (Scheme ). , This result suggested that Δ 9 - cis -THC could originate from CBD or at least that it could be biogenetically related to this compound. In the late 1970s, a paper by Smith and Kempfert described the isolation of Δ 9 - cis -THC from various seized samples of what they referred to as marijuana, observing a direct correlation between the concentrations of Δ 9 - cis -THC and CBD [(−)- 2 ] .…”

Synthesis of Para (−)-Δ8-THC Triflate as a Building Block for the Preparation of THC Derivatives Bearing Different Side Chains

“…Unfortunately, in our initial paper the structure, based on a literature report was not correctly assigned. Such ortho THC regioisomers have occasionally been mentioned as side products in reactions of resorcinols with terpene derivatives, especially when rather small meta substituents are attached to the resorcinol component, and the corresponding regioisomeric products were categorized as “abnormal” THCs. − For example, Antoniotti et al used this “reversed” selectivity to prepare several ortho -THCs in flow . To circumvent this regioselectivity problem and to access a general THC building block for late-stage diversification of the para position, we envisioned using the symmetric phloroglucinol as the resorcinol reaction component in such a cascade.…”

Chemistry and Biological Activity of Tetrahydrocannabinol and its Derivatives

“…Some more physical and chemical data on ∆9-THC are listed in Table 1. Because of its two chiral centers at C-6a and C-10a, four stereoisomers are known, but only (-)-trans-∆9-THC is found in the Cannabis plant [5]. The absolute configuration of the 4 T. Flemming et al…”